Devices controlling and regulating an air flow

ABSTRACT

A device for regulating the temperature of premises by a secondary air flow blown therein, comprises an upstream duct communicating with elements for supplying pressurized air, ending in a converging element emerging into a downstream duct communicating with the premises. The device is characterized in that a substantially rotating solid, capable of being positioned along the convergent element longitudinal axis, is arranged at least partially upstream of the outlet thereof, so as to define between the substantially rotating solid outer surface and the convergent element inner wall with a ring-shaped channel the size of which depends on the position of the solid relative to the wall.

CROSS REFERENCE TO RELATED APPLICATION

This is the 35 USC 371 national stage of international applicationPCT/FR98/02005 filed on Sep. 18, 1998, which designated the UnitedStates of America.

1. Field of the Invention

The present invention relates to improvements to devices intended forensuring temperature regulation of a plurality of premises with the aidof a single incidental air flow at given pressure and temperature, italso concerns a device for controlling the flow parameters of a pulsedair flow in a premises.

2. Background of the Invention

It is known that one of the essential difficulties in the domain of airconditioning is that of delivering to a series of premises, of which thecalorie needs are very different from one another, from a single supplyfurnishing air at a determined pressure and temperature, the quantitiesof air and the calories/negative calories which are necessary for eachof these premises.

In this type of installation, it is usual to adjust the quantity ofcalories/negative calories which is distributed to a specific premisesby controlling the air flow rate which is supplied thereto. Thedifficulty comes from the fact that it is possible to vary this air flowrate only in very narrow proportions as, on the one hand, one is obligedin any case to maintain in the premises a minimum air flow rate, calledhygienic flow rate, and, on the other hand, in particular for reasons ofcomfort of the premises, this air flow rate cannot be increased beyond areasonable value without causing discomfort for the users.

One solution consists in calling upon so-called induction supply means,in which there is blown via a convergent central duct a certain airflow, called primary air, coming from the power plant which entrains byinduction a secondary air flow which is extracted from the premises, andit is the resulting flow, namely the one constituted by the primary airflow and the secondary air flow, which is blown into the premises. It isthus possible, by reason of the resulting thermal equilibrium of themixture of these two air flows, to call upon primary air whose extremetemperatures (minimum or maximum) are respectively lower or higher thanthose acceptable in the premises.

Applicant has observed that, if the flow rate of the primary air isvaried, the corresponding variation of the air blown into the premisesis not proportional to this variation but is below it. For example, whenthe primary air flow rate is reduced, the quantity of air blown into thepremises is reduced in a lesser proportion. It has thus been ascertainedthat, in one embodiment, for a primary air flow rate passing from 115m³/hr. to 26 m³/hr. (or a ratio of 4.4), the flow rate of blown airpassed from 340 m³/hr. to 230 m³/hr. (or a ratio of 1.5). Under theseconditions, since the calories/negative calories which are supplied to apremises are brought thereto by the primary air, it is thus possible toreduce the quantity of calories/negative calories brought to thispremsies while maintaining therein the air flow which is necessary forthe comfort of its occupants. Conversely, it is also possible toincrease the quantity of calories/negative calories supplied to thepremises without blowing therein an air flow such that it would causediscomfort to its occupants by reason of the considerable differences intemperature between the blown air and the air of the premises.

It has been proposed, in particular in Patent EP-A-0531508, to arrangeupstream of a convergent element used in an air-conditioninginstallation employing induction means, air flow rate control meanswhich are constituted by a register system comprising a flap with whichthe primary duct is more or less obturated as a function of the flowrate which it is desired therefor. The flow rate control means of thistype present the drawbacks, on the one hand, of considerably disturbingthe quality of the flow and thus of reducing the efficiency of thedevice and, on the other hand, of generating a very considerable noise.Now, it is known that one of the essential qualities of anair-conditioning installation is precisely to be able to restore in apremises a given air flow at a given temperature, with a sound levelwhich is as low as possible.

SUMMARY OF THE INVENTION

The present invention has for an object to propose improvements toair-conditioning systems, whether or not they call upon induction means,making it possible to adjust the flow rate of the primary air withoutprovoking serious disturbances on the one hand at the level of the flowof the air flux and, on the other hand, at the level of the noisegenerated by the installation.

The present invention thus has for its object a device regulating thetemperature of premises by means of an air flow blown therein,comprising an upstream duct communicating with means supplyingpressurized air, ending in a convergent element emerging into adownstream duct communicating with the premises, characterized in that asubstantially rotating solid, capable of being positioned along thelongitudinal axis of the convergent element, is arranged at leastpartially upstream of the outlet thereof, so as to define between theouter surface of the substantially rotating solid and the inner wall ofthe convergent element a ring-shaped channel the size of which dependson the position of said solid relative to said wall.

The convergent element will preferably be of circular cross-section. Thecross-section of the convergent element may also be of polygonal shape,and the substantially rotating solid may have a cross-section of thesame shape in order to provide between these two elements a stream ofair of substantially constant thickness.

However, according to the invention, the cross-sections of theconvergent element and of the substantially rotating element may equallywell be of different shapes so as to provide therebetween a minimumoutlet section.

In an embodiment of the invention, the maximum outer diameter of saidsubstantially rotating solid is slightly larger than that of thedownstream orifice of the convergent element.

This solid may be constituted in particular by a sphere or, preferably,by a cone or conical frustum of which the upstream part is of rounded,and even semi-spherical shape.

The solid may be maintained inside the convergent element by a rod axialthereto. This rod may be threaded so as to be screwed in a fixed ringforming a nut, which enables it to be positioned axially with respect tothe convergent element. Maintenance in position may be ensured by acounter-nut. Interestingly, the ring forming nut may be maintained by adevice diffusing the air streams, the latter itself being able to beconstituted by a heat exchanger making it possible to adjust thetemperature of the air delivered by the convergent element.

The substantially rotating solid may also be adjustably mounted insidethe convergent element. Such an embodiment makes it possible, when thisis desirable, to modify during operation the axial position of thesubstantially rotating solid. It is thus possible, without dismantlingthe installation, to vary the air flow rate in considerable proportions,possibly going as far as total obturation of the outlet orifice, whichthen enables non-used premises not to be treated (heated or cooled).

The present device is in particular adapted to function jointly withinduction means and, to that end, the downstream duct will comprise,downstream of the convergent element, means for communication with asuction orifice arranged in the premises.

The present device is also interesting in an installation in which theratio of the cross-section of the outlet orifice of the convergentelement with respect to the cross-section of the downstream duct isincluded between 0.06 and 0.50, the downstream duct being closed fromthe outside in its upstream part, so that it gives rise to a peripheralair flow designated in the present Patent by “internal induction”.

BRIEF DESCRIPTION OF THE DRAWINGS

Forms of embodiment of the present invention will be describedhereinafter by way of non-limiting example, with reference to theaccompanying drawings, in which:

FIG. 1 is a view in horizontal and longitudinal section of a firstembodiment of the invention.

FIG. 2 is a view in partial longitudinal section on a larger scale of avariant embodiment of the invention, the substantially rotating solidbeing in position of opening.

FIG. 3 is a partial longitudinal sectional view of the variant shown inFIG. 2, the substantially rotating solid being in position of obturationof the convergent element.

FIG. 4 is a partial longitudinal sectional view on a larger scale of asecond variant embodiment of a device according to the invention.

FIG. 5 is a view in transverse section at the level of the outlet of aconvergent element of a variant embodiment of the invention.

FIG. 6 is a view in partial longitudinal section of a variant embodimentof the invention.

FIG. 7 is a view in transverse section of FIG. 6 along line VII—VIIthereof

FIGS. 8, 8 a and 8 b are views in transverse section of threeembodiments of the invention.

FIG. 9 is a view in partial longitudinal section of a variant embodimentof the invention.

DESCRIPTION OF THE PREFERRED EMBODIMENT

FIG. 1 shows a supply duct 1 of circular cross-section of which theupstream end is in communication with an air-conditioning plant (notshown in the drawing) and of which the other end receives by fit theupstream end of a conduit element 5 whose downstream part 3 ispositioned in a duct 6 in communication with the premises to be treated.The downstream part 3 of the conduit element 5 comprises an orifice 7,of transverse axis, which is in communication by a duct 9 with thepremises to be treated. A convergent element 11 is disposed in theconduit element 5. This element 11 comprises a cylindrical part 11 afollowed by a convergent part 11 b of outlet diameter d. The conduitelement 5 also receives an air stream diffuser element 13 which, in thepresent example, is advantageously constituted by a heat exchangermaking it possible, in addition, to adjust the temperature of the airwhich traverses it, and consequently of the air delivered by theconvergent element 11.

The device functions in known manner in accordance with the principlesof induction. A flow rate Q, coming from the power plant (called primaryair flow rate) is blown under a pressure P and at a temperature T, intothe diffuser/exchanger element 13, then into the convergent element 11from which it emerges to suck by induction a certain air flow rate q inthe premises via the duct 9, which flow rate is blown into the premiseswith the primary air Q.

According to the invention, there has been arranged inside theconvergent element 11 a rotating solid 15 of spherical shape which isfast with a rod 17, of which the end opposite the solid 15 is providedwith a threading. This latter allows screwing of the free end of the rod17 in a threaded sleeve 19 arranged at the centre of thediffuser/exchanger 13. The longitudinal positioning of the solid 15 isensured by screwing the threaded part of the rod 17 more or less in thesleeve 19. Said solid is maintained in the determined chosen position byimmobilisation means such as in particular a counter-nut 22.

As shown in FIGS. 2 and 3, the solid 15 a may also be constituted by acone of which the upstream face is semi-spherical in shape, and thepossible stroke of the threaded rod 17 may be sufficient to ensurecomplete obturation of the outlet orifice of the convergent element 11.This form of embodiment of the invention thus makes it possible inparticular to stop blowing in unoccupied rooms, which represents asaving at the level of the operational costs of the installation.

It has been observed that such a shape of rotating solid wasparticularly efficient both from the standpoint of a good flow of theair streams and from that of silence in operation.

Measurements of noise emission were thus made on such a device. Thelatter presented the following mechanical characteristics:

inner diameter of the downstream duct 3: 125 mm

conicity of the convergent element 11: 21°

outer diameter of the semi-spherical part of the rotating element 15 a:50 mm

conicity of the rotating element 15 a: 21°.

A premises (not shown in the drawing) was supplied with an air flowcorresponding to the maximum flow rate capable of being furnished by thedevice and which was 120 m³/hr. It has been observed that, for this flowrate, the sound level attained in the premises was 31 dB(A). Therotating element 15 a was then displaced so as to partially obturate theoutlet orifice of the convergent element 11 and obtain in the premises aflow rate of 50 m³/hr. It was then observed that the noise levelgenerated in the premises was 30 dB(A), viz. a value less than what itwas previously. The rotating element 15 a was then displaced so as toobturate the outlet orifice of the convergent element 11 virtuallycompletely and the noise level generated by the device in the premiseswas measured, which was then 30.5 dB(A), i.e. a value lower than thenoise level at full flow rate. By way of comparison, it will be notedthat the flow rate reducer devices of the prior state of the art, suchas those with iris or mobile flaps, attain, for identical operatingconditions, sound levels of the order of 40 dB(A) to 45 dB(A).

Contrary to the devices of the prior state of the art, such a flow ratereducer device produces during operation a noise level which not onlydoes not increase in position of total or partial obturation, but, onthe contrary, decreases.

The device according to the invention thus proves particularlyinteresting for effecting reductions of air flow rate when it is desiredthat such reduction of flow rate be effected under particularly silentconditions.

In order to be in a position to blow into the premises a minimum airflow rate, called hygienic air flow rate, it is possible, as shown inFIGS. 6 and 7, to provide in the solid 15 longitudinal conduits 16 whosetotal section of passage is able to create a primary air flow ensuringsaid minimum flow rate in the premises.

In an embodiment of the invention shown in FIG. 4, the positioning ofthe rotating solid 15 b with respect to the convergent element 11 may becontrolled without having to intervene technically on the installation.To that end, the diffuser/exchanger element 13 is provided in itscentral part with two threaded rings 23 in which is screwed the threadedrod 17 which supports the rotating solid 15 b. A motor 25 drives inrotation a pinion 27 which is in mesh with that part of the threaded rod17 included between the two rings 23. By rotating the motor 25 in onedirection or in the other, the displacement of the solid 15 in onedirection or in the other and therefore the positioning thereof at thechosen place of the convergent element, are thus obtained.

It is, of course, possible, within the framework of the presentinvention, to use rotating solids presenting shapes different from thosedescribed hereinbefore. A solid of the type shown in FIG. 4 might forexample be employed, i.e. an element of substantially truncated shapewhose ends are of semi-spherical shape, which might be interesting incertain forms of embodiment from the standpoint of space requirement.

In an embodiment of the invention shown in FIG. 5, the convergentelement 11 comprises on its periphery a series of undulations 29 whichmay take various shapes and make it possible to increase the quantity ofinduced air. In effect, it is known that, in induction systems, theseundulations make it possible to increase the surface of contact with thepulsed air, which improves the induction rate and the stability of theflow. In the present embodiment, when the rotating solid 15 is inposition of obturation, as shown in FIG. 3, the outlet of the convergentelement 11 is not totally obturated. An outlet surface may thus beprovided which is sufficient to create a primary air flow making itpossible to blow into the premises to be treated a sufficient flow toconstitute the hygienic air flow.

According to the invention, a convergent element whose outlet orifice isperfectly circular may, of course, also be used, and a substantiallyrotating solid which has a series of grooves hollowed out therein,particularly of truncated shape, also making it possible to create, whenthe rotating solid is in extreme position, a minimum surface of passagefor the primary air.

As shown in FIG. 8, it is possible to use a convergent elementcomprising undulations 29′ and a rotating solid 15′ provided with meansfor immobilization in rotation and which would comprise grooves 21disposed opposite the undulations 29′ in order to constitute therewithconduits making it possible to define, when the outer face of the solid15′ is in contact with the inner face of the convergent element 11, aminimum primary air outlet section. For the same purpose, as shown inFIG. 8a, it is also possible to call upon a substantially rotating solid15′ of which the cross-section is polygonal in shape, for examplehexagonal, the cross-section of the convergent element 11 itself beingof circular shape.

As shown in FIG. 8b, a convergent element 11 of polygonal cross-sectionand a rotating solid 15 of circular cross-section might also be calledupon.

As shown in FIG. 9, the present invention may also be carried out in aninstallation where the induction is effected in so-called “internal”fashion. In effect, it is known that, in this mode of induction, thereis no orifice for supply of secondary air coming from the premises, butthe outlet orifice of the convergent element is arranged to present across-section s much smaller than that of the duct 3 in which it opensout, so as to create at the level of the latter a return air current,called “internal induction”. In such an embodiment, the ratio of thecross-section s of the outlet orifice of the convergent element 11 withrespect to the cross-section S of the downstream duct 3 is includedbetween about 0.06 and 0.50.

The present invention is also particularly interesting in more generalapplications not calling upon phenomena of induction.

In effect, it has been observed that, contrary to the flow rate reducingdevices of the prior state of the art which, as mentioned above, are asource of considerable noise, the present invention made it possible toreduce the flow rate furnished by a convergent element withoutnoteworthy increase in noise, and even, in certain embodiments, with areduction thereof.

What is claimed is:
 1. A device for regulating the temperature ofpremises by blowing an air flow in the premises, the device comprising:a supply duct having a first end communicating with means for supplyingpressurized air, and a second end; a conduit element extending in thedirection of a longitudinal axis and having an upstream endcommunicating with said second end, and a downstream end; a convergentelement positioned in said conduit element, and having an inner wall andan outlet orifice; a substantially rotating solid body having an outersurface and positioned along said longitudinal axis; said solid bodybeing structured and arranged at least partially upstream of saiddownstream end so as to define a ring-shaped channel between said outersurface and said inner wall; said ring-shaped channel having a sizewhich depends on the position of said solid body relative to said innerwall; an air stream diffuser positioned in said conduit element upstreamof the convergent element; and a downstream duct having an inlet endcommunicating with said downstream end and an outlet end communicatingwith the premises.
 2. The device according to claim 1, wherein the airstream diffuser comprises a heat exchanger for adjusting the temperatureof the air delivered by the convergent element.
 3. The device accordingto claim 1, wherein the convergent element has a circular cross-section.4. The device according to claim 1, wherein the solid body has a maximumouter diameter which is slightly larger than that of the outlet orificeof the convergent element.
 5. The device according to claim 1, whereinthe solid body comprises a sphere.
 6. The device according to claim 1,wherein the solid body comprises a substantially conical or truncatedvolume, having an upstream part which is rounded, and has asemispherical shape.
 7. The device according to claim 1, wherein thesolid body is maintained inside the convergent element by a rod axialthereto.
 8. The device according to claim 1, wherein at least one of theinner wall of the convergent element and the outer surface of the solidbody has such a shape so as to define therebetween a minimum outletsection.
 9. The device according to claim 1, wherein the solid body istraversed by at least one longitudinal conduit for ensuring a minimumoutlet section.
 10. The device according to claim 1, wherein the ratioof the cross-section of the outlet orifice of the convergent elementwith respect to the cross-section of the downstream end ranges betweenabout 0.06 and 0.50, and the downstream end is closed from the outsidein its upstream part, so as to produce a peripheral flow, called“internal induction”.
 11. The device according to claim 1, wherein thedownstream end comprises, downstream of the convergent element, meansfor communicating with a suction orifice arranged in the premises.